A liquid crystal display (LCD) is a kind of flat panel display (FPD), which shows images by the property of liquid crystal material. Compared with other display devices, the liquid crystal display has the advantages in lightweight, compactness, low driving voltage and low power consumption, and thus has already become the mainstream produce in the whole consumer market. However, the liquid crystal material of the liquid crystal display cannot emit light by itself, and must depend upon an external light source. Thus, the liquid crystal display further has a backlight module to provide the needed light source.
Generally, the backlight module can be divided into two types: a side backlight module and a bottom backlight module. Traditionally, the backlight module uses a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL) or a semiconductor light emitting element as the light source, wherein the semiconductor light emitting element mainly uses a light emitting diode (LED) to emit light. The light-emitting-diode is better than the cold cathode fluorescent lamp in energy saving, longer lifetime, lightweight and compact volume, so that there is a trend to gradually replace the cold cathode fluorescent lamp and thus the LED will be the mainly light source of the backlight module for the liquid crystal display in the future.
Nowadays, the light emitting diode is usually assembled in a semiconductor chip type to be used as a LED package structure, and finally connected to a fixed plate of the backlight module. But, the disadvantage of the LED package structure is that the temperature thereof during working is very high. If the fixed plate of the backlight module could not timely dissipate heat generated by the LED package structure, not only the temperature of the surroundings of the LED package structure will obviously raise and result uneven temperature distribution in each of display blocks of the liquid crystal display, but also the high temperature of the display blocks of a liquid crystal display panel adjacent to the LED package structure may cause a reddish phenomenon due to the high temperature, resulting in affecting the imaging quality of the liquid crystal display. Moreover, the raised temperature of the light-emitting-diode during working may easily affect the emitting efficiency and the working stability thereof, so that the lifetime thereof also may be lowered due to a long-term high temperature status. Also, if the LED package structure are simply attached to the fixed plate only by an adhesive or fastened on the fixed plate by screws, the LED package structure and the fixed plate can not be directly in thermal contact with each other (or an insulation adhesive is sandwiched therebetween, or the interfaces therebetween are not in tight contact with each other), so that the heat-dissipation efficiency thereof will be affected in a certain degree. Besides, after staying at a high temperature condition in a long time, the adhesives may be deteriorated and loss the viscosity, so that the LED package structure will be separated from the fixed plate. If the heat of the LED package structure could not be timely taken off by the fixed plate, there will be a potential risk in overheat damage for the LED package structure.
So, it is necessary to provide a light-emitting source package structure for the LEDs of the backlight module to solve the heat-dissipation problems existing in the conventional technology.